A new peracid reagent is described for the selective epoxidation of olefins. This reagent is the first system to show selectivity between cis and trans olefins and research is proposed to develop it into a reagent capable of asymmetric epoxidation. Other hydroperoxides imbedded in a chiral or hindered environment are also proposed including Alpha-hydroperoxy ethers and peracids with geometries altered by intramolecular hydrogen bonds. The ultimate goal is to provide organic synthesis with reagents of enzyme-like selectivity. These reagents could open new strategies for the synthesis of highly-oxygenated natural products such as macrolides and carbohydrates.